octa = [ 1, 8, 21, 40, 65, 96, 133, 176, 225, 280, 341, 408, 481, 560, 645, 736, 833, 936, 1045, 1160, 1281, 1408, 1541, 1680, 1825, 1976, 2133, 2296, 2465, 2640, 2821, 3008, 3201, 3400, 3605, 3816, 4033, 4256, 4485, 4720, 4961, 5208, 5461, 5720, 5985, 6256, 6533, 6816, 7105, 7400, 7701, 8008, 8321, 8640, 8965, 9296, 9633, 9976 ]
